1. Field of the Invention
The invention relates to a cable entry, for example for connecting a fiberoptic cable to a remote radio head (RRH) in a mobile radio antenna.
In mobile communication systems, so-called remote radio heads (RRHs) are used. Said remote radio heads permit a greater distance between the base station and the antenna. The RRHs are generally connected to the base station via fiberoptic lines (fiberoptic cables). In order that the fiberoptic lines can be connected in a simple manner using the connectors fixed thereto, cable entries with holding devices in front of them are used.
2. Discussion of Related Art
Cable entries are known from the prior art. Said cable entries comprise an appliance-side flange with a coupling thread, a fitting opening and a cable-side plug-in part with a union nut, which can be operatively connected to the coupling thread. The flange is fastened on the outside to a housing of an RRH. LC connectors fastened to the cable in the interior of the RRH can be operatively connected to an SFP module, for example, through the fitting opening. The SFP module (also referred to as a mini-GBIC) is a standardized module for network connections. The diameter of the fitting opening is generally of such a size that the SFP module can be pushed through the fitting opening for fitting purposes.
The LC connectors conventionally used and known from the prior art are standardized optical connectors with a basic body with a sprung locking arm which protrudes upwards and towards the rear at an angle and has two locking shoulders which protrude outwards laterally. Whilst being plugged into a socket provided for this purpose, the locking arm is moved downwards, with the result that the locking shoulders snap into cutouts provided for this purpose in the mating piece. In order to be unlocked, the locking arm needs to be pressed against the basic body until the locking shoulders are unlocked. Then, the LC connectors can be withdrawn from the mating piece. Two LC connectors which are arranged laterally next to one another and are connected to one another via a holder are often plugged in or unlocked at the same time. In order for joint unlocking to be possible, the holder in the case of conventional connectors has a clip, by means of which both locking arms can be unlocked at the same time. The clip is arranged behind the locking arms and protrudes forwards and upwards. By virtue of the clip being pressed forwards and downwards onto the locking arms, said locking arms are released. In particular in difficult spatial conditions, unlocking is difficult since the force required for depressing the clip is in the opposite direction to the removal direction.
The cable entries known from the prior art are relatively difficult to fit in the field since the LC connectors first need to be connected to the SFP module. For this purpose, said SFP module needs to be reached through the fitting opening. In the process, care needs to be taken to ensure that the fiberoptic cable or the LC connectors fastened thereto, neither of which have any strain relief at this point in time, are not damaged. Only then can the union nut be screwed onto the thread of the flange. In this case, care additionally needs to be taken to ensure that the cable is not twisted off by the sleeve being screwed on.
U.S. Pat. No. 7,338,214 by Tyco Electronics Corporation was granted in March 2008 and discloses a method and a device for sealing a plug-in part of a cable entry for optical connectors. Two LC connectors can be arranged fixedly in an outer housing of the plug-in part via an adapter. This device has the above-described disadvantages.
EP 1 018 660 A2 by Delphi Technologies Inc. was published in July 2000 and discloses a connecting device for coupling a fiberoptic conductor with an optoelectrical transducer. The device has a base which can be fastened on a printed circuit board. A cable-side connector part can be snapped into an opening, in which it is held by means of a spring.
EP 0 154 781 A2 by AMP Incorporated was published in 1985 and discloses an optical connector arrangement with a housing-side flange part, to which an optical connector can be connected on both sides. The two connectors are aligned coaxially with respect to one another in a fitted state and in the process enter into an operative connection with one another.
The same Applicant has disclosed a cable entry which can be fitted in a simpler manner in comparison with the prior art and which has further improvements. The cable entry has a housing-side flange with a fitting opening for passing through a cable. A boom projecting from the base plate of the flange has a holding device at its opposite end, said holding device being suitable for accommodating a mating piece fitted to the cable before a fastening sleeve is screwed over both of these parts. This provides the possibility of the cable being protected in respect of strain relief before the connectors are connected.